Java application of old technology integration
Class: Junior
Scott W. Ambler (scott.ambler @ ronin-intl.com), president of Ronin International
November 16, 2000
Described here by following the four public integrated strategy of one or more may be Java, J2EE, EJB-based applications with existing legacy systems to facilitate integration.
Very few projects have to start from scratch team (usually refers to green development) benefits. In the alternative, to the cold and hard in the development of new applications, the majority of Java project team needs to consider the existing old system. Maybe you need access to the existing inventory control system, the old customer databases or mainframe-based access control security services. If this is the case, you will have the old system integration, known as the "Enterprise Application Integration (EAI)". Bring to your team's advantage is that, if the old system designed to be reasonable, then you can use a large number of existing functional. However, if the old system designed to be unreasonable, or simply did not consider the design to integration, then you will find that integration is an important part of the project. When there is not enough documentation or when the owner of the old system are unwilling to work with your team cooperation (Never underestimate the role of policy on the project), this is particularly true.
DS Linthicum in the Enterprise Application Integration recommended four of the old system integration method:
- Data-level integration from a Java application's point of view, this type of integration through the session concentrated in the bean or entity bean access to the old database or documents. It included from the old system, and data access for the newly developed special-purpose data supply visit. XML is usually used for such integration technology, because XML is platform-independent data sharing methods. The advantages of data-level integration, can be quite direct and swift implementation. Shortcomings, including an increase of the data between the application coupling, thereby increasing your maintenance burden can not access important acts, such as data validation and key business rules and the need for the design of the data prepared by the poor important data cleaning / formatting code .
- Application Programming Interface integrates the use of this method, you can use the procedures exposed by the application of the application programming interface (API) to access the old system-in-package data and functions. Application Programming Interface integrates the advantages of this method in a certain standard in the industry; many packages (such as SAP and PeopleSoft) can be included by the Java Native Interface (JNI) code to the C-API. The main disadvantage is that in your organization internally developed software rarely defined API; API may have limited the scope of your needs and can not act (or the way you need it), in fact, is usually oriented API function , and not object-oriented.
- The use of this method-level integration, business logic can be called as the sharing of software or operating methods sharing pool. For example, updating customer data, verify credit card transactions or depositing money in bank accounts and other public can operate in all application programs have access to public resources or the use of reusable framework. Method-level integration advantages is that it usually provides the public the detailed functional business visit a wide range of applications (including Java and non-Java) can access these operations; call is direct. Disadvantage is that, if everyone methods are not effective stent, then the public and meticulous method of characteristics would be difficult to support the public service or technical support services, such as security and access control.
- User interface-level integration technology through the user interface on the visit to the existing applications, such as screen clippings process, in which mimic a user's keystrokes to achieve interaction with the old software. Screen clip is based on the aggregation of Web sites (such as Vertical One) the use of the public, to demonstrate financial or other types of information personalized view. The advantage is, this is the old time-tested and integrated common method, and many user interface test tools (such as Mercury Interactive's WinRunner or Rational Corporation of SQA Suite) are to use it. The main disadvantage is that this method may be very slow: the need for the old application is drawing your clippings screen, but the user interface of the old by any changes need to integrate code changes.
Fortunately, the old simple integration - especially when considering the design of the old system to integrate - can usually be handled by middleware products, such as Tibco Inc ActiveEnterprise middle of the line, IBM MQSeries product family and the iPortal Integration Server Iona. However, when integration than confirmed by the organization based middleware with things more complicated, you will find that you need to prepare their own integration code, commonly known as (wrapper) code. Table 1 shows the Java code in the application of a variety of options, each described how to use Java technology applications with the old system integration.
original English text.
Ronin International, the company is a specialized object-oriented process to provide guidance, architecture modeling and Enterprise JavaBean (EJB) development consulting business. Or his own book and the other people of the several development of the object-oriented books, including the recently published The Object Primer 2nd Edition, the book details outlined in the theme of this paper. Through scott.ambler @ ronin-intl.com contact with him, his website at www.ambysoft.com.
Tags: the core java technology